1. Field of the Invention
The present invention relates to a meter module and a connecting device thereof which can facilitate assembling of electric cables and electrical apparatus in an instrument panel portion in a car.
The present invention also relates to a protector suitable for protection and storage of wiring harness arranged for example in an instrument panel portion in a car, and to a connecting device of instrument wiring harness.
2. Related Background Art
There are a number of electric devices, control circuit units for controlling or monitoring them, meters, indicator lamps and switches densely arranged around an instrument panel portion. Thus, the number of electric cables in instrument wiring harness becomes enormous, increasing the volume, the weight and the complexity of wiring. A lot of labor and time is needed for setting of wiring and for connector connection between the harness and the electric devices, and maintenance is very hard.
To relax the situation, Japanese Patent Publication No. 57-38457 describes an idea to simplify the wiring arrangement of wire harness and then to prevent an increase in volume or in weight, in which a plurality of electric junction boxes are scattered in some proper portions in a car, each junction box housing a branch junction portion in wiring harness, a number of fuses as circuit protecting members, and relays as control parts.
FIG. 36 is a wiring diagram for a tail lamp system using such an electric junction box. Reference numeral 1 designates a car body, 91A, 91B tail lamps, 92A, 92B clearance lamps, and 93 an engine. A battery (not shown) is set in an engine room 1A. Arranged around an instrument panel 1B are a meter panel 95 having a tail lamp warning lamp 94, a tail relay 96, an electric junction box 98 provided with a main fuse 97A, a tail fuse 97B and a meter fuse 97C, a lamp breakage inspection relay 99 and a tail switch 100.
When the tail switch 100 is turned on, contacts in tail relay 96 are closed to activate the circuit including the tail fuse 97B so as to light the lamps 91A, 91B, 92A, 92B. If either one of the lamps 91A, 91B is broken, the lamp breakage inspection relay 99 functions to light the warning lamp 94 in the meter panel 95.
FIG. 37 is a block wiring diagram to show the wiring around the meter panel (combination meter) 95 in combination with the electric junction box 98, the lamp breakage inspection relay 99, and the control circuit unit 96 such as a speed control relay and an integration relay as described above.
Mounted in the meter panel 95 are numerous meters 101 such as an oil gauge, a battery indicator, a speedometer, and a tachometer, movements 102 therefor, and lamps 94 for indication, warning or illumination. The speedometer 101A and the tachometer 101B are provided with dedicated control circuits 103A, 103B, respectively. Further, the control circuit units 96 such as the speed control relay and the integration relay are separately arranged. Therefore, the number of power lines and signal lines is still large to connect between the elements. The complexity of wiring will still remain in the arrangement with the limited number of electric junction boxes 98.
Then, Japanese Laid-open Patent Application No. 2-45238 discloses an attempt to further simplify the wiring harness around the instrument panel portion by such an arrangement that an internal circuit in the meter panel is arranged to include a branch circuit having a joint connection portion for connection between the meter panel and the wiring harness, whereby the meter panel takes over a partial role of the branch connection portion in wiring harness to reduce the number of circuits and the number of connection cables inside the electric junction box.
Also, Japanese Laid-open Patent Application No. 4-266537 discloses a circuit structure as shown in FIG. 38. In the circuit structure, switches and meters (not shown) are mounted on a cluster 105 in instrument panel portion 104, a flexible printed-wiring board 106 constituting electric circuits therefor is bonded onto the back face of the cluster, and electronic control boards 109A to 109F, in which electronic functional components 108 such as memories and operational elements necessary for electronic controls of the switches and meters are scattered, are incorporated and connected to terminals of the wiring board 106.
Even if the internal circuit in the meter panel takes over a part of wiring harness or branch circuit of electric junction box, there is a limit on simplification of wiring harness as long as the control circuit units for various electric devices are arranged as separately scattered. Thus, the conventional technology cannot match a further progress in electronization as expected in seeking the safety and the cabin comfortability of car.
Also, when the electric circuits (flexible printed-wiring board) for the switches and meters, and the electronic control boards are arranged as scattered directly on the back face of cluster, a great advantage is present in that the control circuit units are concentrated on the back face of cluster, on one hand. On the other hand, the arrangement has such a technical difficulty that the units must fit in with the shape of recessed or protruded back face of cluster, and the design and production must be changed depending upon the type of car, the grade or a partial change of specifications, resulting in increasing the production cost because of production of small quantity but many types.
Further, the number of electric devices set in the instrument panel portion is still large even in the arrangement that the internal circuit in the meter panel take over a part of wiring harness or branch circuits in the electric junction box, or in the arrangement that the control circuit units are concentrated on the cluster back face by directly scattering the electric circuits (flexible printed-wiring board) for the switches and meters, and the electronic control boards on the back face of cluster. Therefore, the number of branch lines coming from main lines of wiring harness is not so reduced as long as the conventional methods are employed for connector connection between the wiring harness and the electric devices. Thus, a considerable space is necessary for setting the wiring harness, and a lot of labor and time is still necessary for the setting of wiring harness and the connection with the electric devices.